SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'eb8d98dd856b96932880d74aa534c996c4825e858fc0155e8d0db80d6f52c543' 
  AND token = 's10Nc7us88WS3vD0UdCLWlhOB9t+yQsJGWE6QHzdpBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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