SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3fa87fee15cd1afc1801815d2e5470c2614b2326bd13af6c1383af682a6ceb9' 
  AND token = 'LSNcH6HEj1Mt+1+JGg5TWFNFrqtzv2Z/OJBB9dZPhUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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