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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15ab7b9e85964296fcb78b7a9e47308a78d0cdb7b337e696d7832ffecce7bfd0' 
  AND token = '3irT1KET5gYQ/6sQeEnwH+ScZKoyiFrvxF+LEC7L+Uw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}