SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c6970ff212a186b5fbd79feb166a45d4ea59a21ecbc7d34b78022f8def90127' 
  AND token = 'ENeNW4R9jvCAgKni1YReOp0s+VQwTrKT/mBrUO8b4g0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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