SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a1c9fdba2fb498c5993ed3b69c59494155b574cc89eee8807a69aa6f907449e' 
  AND token = 'SndT1Vg10Gd9I6Ey9bnKlNH7bPgOh2ohqc7++2gZ5+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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