SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6b29eed1c58e2fe60903c3bebeb84f67f9ace11d59d06a64f06875098ddd9c12' 
  AND token = 'kl3OT/koFb0A+9/O/ozHvPQumIklOxFyHIRRy8PlunM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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