SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87f0cf2303d557f79656c937c613cf1bc2b2aeea2496c536d6493521faa08b1c' 
  AND token = '63Fbgn30+zR8WsFPQdy/DcCOYkmwF1jcouQdnqxRO+A=' 
  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"
    }
  }
}