SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5909fe342cd591b0dcb90bf50a0f1fba57ab8344510cfeb55db25b3dee691b4f' 
  AND token = '4MyUgJ/CMT9uPXEhSkg/pRiqowtQ/YEKRgKLyjWRuZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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