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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a7fa0022d7e600fd4508861c71d78359ad7575a140f7ffe4c4fefb5a7ac828f' 
  AND token = 'xP6wiQww6weYTlnmpTI+Dz924ZCPp6kBekUWjLG+a9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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