SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4560a598bf05d71723702b2a9f864be45864882d00c02cfbdc61de6c8da4a9ac' 
  AND token = '14kE3rEa1tMGr4NhJjp30kKVU/JMYxXZbUzWszQ9vFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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