SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3bd85ab2354cf3fb8a7ee0e52e511656f25c15292901798eb827d5e90b00c9a' 
  AND token = 'Ac4ZRnRhVq/KjvaIYmREJr9UD/kRfXIkevQHJ+pRPwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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