SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fe0049034787dbcb0223f8633e7e510cd98a501ba2b588d97c9aad18e0b70e5' 
  AND token = 'ne21BOwuiRCVVBncP79gYzJ+lV5nunbWPRNhVJ5cYu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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