SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8989398e05b402457b082fd7f520fa29089575ffa04d6cf4b4d08428b678e52' 
  AND token = 'Gx9at3zINcyJlzhmfp2rIeRIwaj3YePXmithbFLRwoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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