SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '19304f015e0fa57eb3e97f16cfae5679c302723f22d54d8c62729582a946433e' 
  AND token = 'jLxIp3RRF/zzQvc0cjc+Dtzz7mY/PrCenLC09VCegNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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