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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04d3f37a6fe4596fcd3d1c57dfd593f9e0e3ec7f7f283515667d64fd7dfe902f' 
  AND token = 's6xRqBmZMsni/o7BlfrE8GCwlf90QG0OG4Uk4eX+HFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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