SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27010b2f414688e1ddcb5ee4aa07beb2bb6de75df3a4cd0b465191e53a0ce279' 
  AND token = 'jr6CWXMxl52c7b8knld1AGCUzvy88BH91cxrY5VxjQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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