SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a85aac9d0fb48f31ced9ea513c5cf6d0585535adf6e456d965f590aed1205ce2' 
  AND token = 'HEmh1WPKM9yrfdR7/jUkFllj5MfdALJlKTBODLKNzQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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