SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f66d0463441a4884ff248dc3e5b85531be7fb9e68743a3758f880b433ebba01e' 
  AND token = 'S1fVFzDJxqFXaNFjZOp/CgQBjDGFDLtddOnVV4Y2Jy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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