SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85cbf8083571e25f37028c60adc6760149cae01825da6bd155b299ab8cdde807' 
  AND token = 'eK65TDa1OLIL3FuYY+etNMPGRzYz/8dGbC3p8DVEdL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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