SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '158627f8c90534fda7c6791abea109e29c7d6e854314ff06e226da115a30ba60' 
  AND token = 'w31CApHVCfr+si/BHyh6YI/GVi1PFjzmWrz1ZBIrMMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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