SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ff3c5251f795e122258bd678fee5be697f790b8f72d4207f839db6c922df87be' 
  AND token = '7qy9/R+xb7IgJ2vtLzH+FqPH0ajYs9IvWj+4qipIQ88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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