SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11844733e0f8f16a5c276eb69d85bc4f41eeadf7baa775ea6167b874080c8345' 
  AND token = '/oWm2hL3LiwWeRyGxYKrbPWZMvLI6xCUVFcH4LbQPL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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