SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55a9e206ca821c0283cdfd357fadb212f051bb5625a9ef18f6639697836ae2de' 
  AND token = '5st+EWBYuzf5QNhe8wLeqvqW1928vjWDdLIrB+d7DIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}