SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ab45c27fa66d9fd1930ee28bbefc4c190b25e3de71246831c12e564616ce1ec' 
  AND token = 'JmuW07/FU9X8yNNAK8NM97dEnElM7G1PbltMchSOWhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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