SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7feb700f447db9e4949425a16b93804f27c60a1dc770694aa27acb7b142cbb4' 
  AND token = 'qcf/98TA81GNqZu/i76eB9ldc/xT7LBfCqdEsH9X9p8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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