SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '938b11438cf51142cfa944d8699e00133e340be405a9b0fe777cc4418b98db08' 
  AND token = 'HhAav+0I/78QSMDsgGlYJrDqJUtRq2TKz4jyszC8vbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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