SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3018430ea0b512aeb42ddc71e42ccbeb27ec859840e0268b762856ddd52efea' 
  AND token = 'K1XiyYvkpF+ar8uX2olJlb4iDg5v81rjoUWz2UXA2Yk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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