SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3f8a82d15ceb22b151816d81b9077cd2fb1a2e3a0ce81ec3175cfc14af3e6fb9' 
  AND token = 'urkEJEjgWeu9R7EaXxZJ67/BvX59FVBP7cAeNhxWabE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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