SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d16bd69a185c78d465effdc26fddd3da48e4601518820c34113da25c769ba81' 
  AND token = '7XHG7FawRZJZgm/PMMe5Idsf0+Bcm3Tl19XPQyF2PDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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