SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd366088547081aacc676fda14eb25d42d2b78d6f4825d21070b887a818c0e330' 
  AND token = 'sIJUw6I7VSJPDNPDNAHEgRqE37rCe0OklWRRhvPwngk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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