SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04def34751dad1858f9acdaa02f18e864d539ccf70bbd38e0d597b33d41a2ca8' 
  AND token = 'T+CmrLPKnw4RMAZnkJj9Uc1OaUBC29ET0v/HfgvOVxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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