SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7a39e4f974aabd0df748363b70ebe8fc88b15695cf79dde5827bf75976d00645' 
  AND token = '3n2TDAzDOellukYRTbkS4oKwREdEnChnRawCF3H9ecM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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