SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '372990ce0db569c88246006f6d755702e9dbdd801779c4284f411f941c695557' 
  AND token = 'DahV//FxVk2Pbf5BskF3apio2Xd9284EzQbaDsLdYSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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