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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e5a837b5d45c7882e6d72f3c1127613a43f88f8092bd9c033c6e6322ed7f74e' 
  AND token = 'AUpQqi40KqY4WRs7j5gUhJwu00i7tUILeSCncMhoQxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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