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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5324aaa5d17601d74b9db7efa3f3b2fc9d8677621e9b35d0a676ab29ba8a461' 
  AND token = '4Pp9TC6H+RwRQe9CRPnave0b6ChjEM/ZsPI8ZzId3Kw=' 
  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"
    }
  }
}