SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '486811f76e13276f7dd452c46e0a49cb550195c49a208d2fef78cfdf70aec68a' 
  AND token = 'z8VNH47lARPpwXzahRtaQsSh+W87cDTyxEfcmHG4c9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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