SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4c2ad19e195d29096fa0c342efdf62f20ad9f6153faf642cc32d3e134e813f86' 
  AND token = 'F54oGlYW4gniKFgQp91QubG773T5rOXuI04fyD2wGus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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