SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4903977da15f1fe6265b9349b42f56cc693124b29e53a4ff1bb65351a24a1e68' 
  AND token = 'IBwGDjYp6RlnLAH3B8EggI6Fy4bOByaVNBYsgKyLF7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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