SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18fdf98ce1e43a5d5530deaf00c87135eecdb1dd2d2faeae205074abfd77dcfa' 
  AND token = 'LFlZmVNT8N0vK6aTDZfuEqPN1Qzk6joADNpFa5B4zmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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