SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b3ee8c96082b663f2f29647cc5d6eaa1ad990c8eb0091fd07db1d67053f5ec8d' 
  AND token = '+cKR2N8LOaBHkFSeiUmbLfPH5sdAqBOZXQaSmAvQZws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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