SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8e95a59fd8e011afe0478d2b913f672196aa359e9add47f528990d253b211f6' 
  AND token = 'RTmZaLhWmKL+aBhXzJjGO+//Vkm2Us9VcReyXE6b290=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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