SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '635627eca98a1f238eaec0b386e4730289ff7c9182a8059293a46e84732da507' 
  AND token = '4VHZhxmpAQqNrsqGuLkxIj+Kx33d3UzHSi5fu/92wsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}