SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f8f9e42108f9a81c78c852660e69d81fc938205c3f1305a502a07ec32ef74b1' 
  AND token = 'zqVj7ZSlKM/Jf/F/SDTjYAyq2WeTiyBXTvG/d/kyZnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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