SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e77440a120dbf8a2e664f462b82707b3e883ded936979b2a8484fa983b84325' 
  AND token = 'b4CrmoX2iTaKN8zIp1Usqb3lKoQg1ZQwtKK1VPUYlLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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