SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b2570167a4afde04c65be270a92320f6897207da0e3f2ed93639b3ca8ea08b91' 
  AND token = 'pL5900ENPDdnsxNFOjzJwNMfoDD3PtkWtfaC+opDU/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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