SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cfb95e65855837b63406501c3000986d33fb5b325069d4d0b16eb5a21e8d1a9' 
  AND token = 'sP+gWtdyd2/j08TuvazvzAqU7YM5GwJPMidS/ZAmBkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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