SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9db4560890c32dce7350a034078fbccc628c14eaed5c86d5e84195f5ea7d955' 
  AND token = 'cMdPqODnLCtJoPXCu3RP9R8PlWxJTa1ycU44Ry+7nwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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