SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bb5378c176fc301865163682f3d0f72837fa8d25855366805bc192ee04c119e' 
  AND token = 'ANBqUwJElo+7chbMpFWPh5VU0Sg7+RcrbS4RBJjK7Hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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