SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bec9b0cad3a3f3cc1150505906eaa9e8988fb84a5bcec2d43ad6c018480a0a42' 
  AND token = '/mhUJIlX+ujxcthoadi7ON8dDDxHI3pBEgsyuxDTPJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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