SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0215beba0be7cffd11b995918bd6d378a58c5752d402be7d965df72e661af7b' 
  AND token = '7DkJlKuMP+mdhwzADa3AqwxcVnrGPV2X/OLi2XMimms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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