SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4512df9ddefa305a6f239bde606d253ed0e046e0766cde6f70a950554d81a9d8' 
  AND token = '2DbgKyNPbFBcukO2+adFz1829k/seQOAVvRNMFSrLDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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