SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6dcb7f1f5416658f19995ee36583b30ba8e3a47be41440b0e75a2f9f1ed384ed' 
  AND token = 'spYQcHVpbyPWWu89ITRFassznOZ/f03SJwew8d5GOVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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